Urban and Gill assembled an all-star lineup for the show, which included surprise appearances by Country Music Hall of Fame members Merle Haggard and Don Williams. The concert is a fundraiser for the Country Music Hall of Fame and Museum.

“There’s an enormous amount of duos and groups that have been signed in the last handful of years, and I wanted to feature them and also remind people of the rich history we’ve got of groups and bands in this genre, too,” Urban told CMT.com on Monday.